U.S. patent number 6,439,267 [Application Number 09/895,117] was granted by the patent office on 2002-08-27 for adjustable flow diffuser.
This patent grant is currently assigned to Welker Engineering Company. Invention is credited to Robert H. Welker.
United States Patent |
6,439,267 |
Welker |
August 27, 2002 |
Adjustable flow diffuser
Abstract
When a fluid passes through a conventional elbow, turbulence is
created in the fluid flow. The fluid may not stabilize and return
to a laminar flow until 40-50 pipe diameters downstream. Turbulence
in a piping system can cause a variety of problems such as
measurement error, noise, vibration, and/or erosion. The flow
diffuser of the present invention may be configured as a 90.degree.
elbow for use in a piping system to reduce turbulence and/or
pulsation as the fluid passes through the improved elbow. The elbow
can restore substantially laminar flow in a space of about four
pipe diameters, with nominal pressure drop.
Inventors: |
Welker; Robert H. (Washington,
TX) |
Assignee: |
Welker Engineering Company
(Sugar Land, TX)
|
Family
ID: |
46257813 |
Appl.
No.: |
09/895,117 |
Filed: |
June 29, 2001 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
|
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360424 |
Jul 23, 1999 |
6289934 |
Sep 18, 2001 |
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Current U.S.
Class: |
138/39;
137/625.28; 138/43; 138/46; 251/118 |
Current CPC
Class: |
F15D
1/04 (20130101); Y10T 137/86718 (20150401) |
Current International
Class: |
F15D
1/04 (20060101); F15D 1/00 (20060101); F15D
001/00 () |
Field of
Search: |
;138/37,39,43,46
;251/118,126,127 ;137/625.28,625.3,625.38 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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28 10 118 |
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Sep 1979 |
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DE |
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0 097 312 |
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Jan 1984 |
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EP |
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59140973 |
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Aug 1984 |
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JP |
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Other References
Fisher Controls; "High Performance Control"; 1989; pp. 1-12. .
Fisher-Rosemount; "Type 399A Pilot-Operated Pressure Reducing
Regulator"; Bulletin 71.2:399A-161; pp. 1-24, 1992. .
Fisher-Rosemount; "Whisper Trim I Cage"; Bulletin 80.1:006; Mar.
1997; p. 1. .
Fisher-Rosemount; "Whisper Trim III Cages"; Bulletin 80.1:010; Mar.
1997; pp. 1-4. .
Fisher-Rosemount; "WhisperFlo Trim"; Dec. 1997; pp. 1-10. .
Fisher-Rosemount; "WhisperFlo Aerodynamic Attenuation Trims";
Bulletin 80.3: 010; Feb. 1999; pp. 1-4. .
Pipe Line & Gas Industry magazine; "New gas-pressure regulator
blends features of boots, plugs"; May 1999; pp. 59-71. .
Fisher-Rosemount; "Type EZR Pressure Reducing Regulator"; Bulletin
71.2: EZR Jan. 1999; pp. 1-24. .
Fisher Controls; "Cavitrol V Trim"; Bulletin 80.2: 020; May 1979;
pp. 1-4. .
Fisher-Rosemount; "Cavitrol III One-Stage Trim"; Bulletin 80.1:
010: Aug. 1997; pp. 1-6. .
American Meter Company; "Radial Flow Valves" Aug. 1997; pp. 1-16.
.
Mooney Controls; "2-Flanged Single Port Flowgrid Valve"; 1991; pp.
1-6. .
Pipe Line & Gas Industry magazine; "Testing evaluates
ultrasonic meter installation configurations"; Dec. 2000; pp.
31-35. .
Hydrocarbon Engineering; "Meeting Flow Conditions"; Jan. 2000; pp.
1-4. .
American Gas Association; "Measurement of Gas by Multipath
Ultrasonic Meters"; Jun. 2000. .
American Gas Association; "Measurement of Gas by Turbine Engines";
Apr. 1996..
|
Primary Examiner: Hook; James
Attorney, Agent or Firm: Blackwell Sanders Peper Martin,
LLP
Parent Case Text
CROSS-REFERENCE TO RELATED APPLICATION
This application is a continuation-in-part of Ser. No. 09/360,424
filed Jul. 23, 1999, now U.S. Pat. No. 6,289,934 issued on Sep. 18,
2001.
Claims
What is claimed is:
1. An adjustable diffuser connected to an inlet conduit and an
outlet conduit to reduce turbulence and/or pulsation as fluid flows
from the inlet conduit through the diffuser to the outlet conduit,
the adjustable diffuser comprising: a body defining an inlet, a
receptacle, an elongate discharge nozzle, and an outlet; a cap
removeably attached to the body, the cap allowing access to the
receptacle; a removable flow conditioner sized and arranged to fit
in the receptacle, fluid flowing from the inlet conduit into the
flow conditioner, through the elongate discharge nozzle to the
outlet; the flow conditioner having a plate with a plurality of
vanes defining a plurality of flow passageways so that an exit flow
path from all the passageways is oriented generally towards the
elongate discharge nozzle and outlet; and an adjustment assembly to
rotate and precisely align the flow conditioner, the vanes and the
flow passageways relative to the discharge passageway in the
elongate discharge nozzle and the outlet.
2. The apparatus of claim 1 further including a lock assembly to
fix the position of the flow conditioner after the flow
conditioner, the vanes and the flow passageways have been precisely
aligned with the elongate discharge nozzle and outlet.
3. The apparatus of claim 2 wherein the adjustment assembly
includes: a plurality of gear teeth formed in the flow conditioner;
an elongate adjustment stem having a plurality of adjustment stem
gear teeth on one end and an adjustment knob on the other end so
rotation of the adjustment knob causes rotation of the adjustment
stem gear teeth; and the adjustment stem gear teeth engage the gear
teeth in the flow conditioner so rotation to the adjustment knob on
the adjustment stem causes rotation of the flow conditioner to
precisely align the vanes and the curvilinear passageways with the
elongate discharge nozzle and the outlet.
4. The apparatus of claim 2 wherein the lock assembly includes: an
elongate lock pin sized and arranged to fit in an elongate bore in
the cap; and the lock pin threadibly engaging the bore so rotation
of the pin imparts axial movement to the lock pin causing it to
move away from or to engage with the flow conditioner to lock the
flow conditioner in position when the vanes and curvilinear
passageways are precisely aligned with the elongate discharge
nozzle and the outlet.
5. An adjustable diffuser connected to an inlet conduit and an
outlet conduit to reduce turbulence and/or pulsation as fluid flows
from the inlet conduit through the diffuser to the outlet conduit,
the adjustable diffuser comprising: a body defining an inlet, a
receptacle, an elongate discharge nozzle, and an outlet; a cap
removeably attached to the body, the cap allowing access to the
receptacle; a removable flow conditioner sized and arranged to fit
in the receptacle, fluid flowing from the inlet conduit into the
flow conditioner, through the elongate discharge nozzle to the
outlet; the flow conditioner having a plate with a plurality of
vanes defining a plurality of flow passageways so that an exit flow
path from all the passageways is oriented generally towards the
elongate discharge nozzle and outlet; an adjustment assembly to
rotate and precisely align the flow conditioner, the vanes and the
flow passageways relative to the discharge passageway in the
elongate discharge nozzle and the outlet; and said adjustment
assembly having a pair of opposing axial elongate set screws
bearing against opposing sides of an adjustment lug extending from
the removable flow diffuser, the elongate set screws threadibly
engaging the body so rotation of one elongate set screw and
counter-rotation of the opposing set screw, causes movement of the
adjustment lug and the removable flow diffuser.
6. An adjustable diffuser connected to an inlet conduit and an
outlet conduit to reduce turbulence and/or pulsation as fluid flows
from the inlet conduit through the diffuser to the outlet conduit,
the adjustable diffuser comprising: a body defining an inlet, a
receptacle, an elongate discharge nozzle, and an outlet; a cap
removeably attached to the body, the cap allowing access to the
receptacle; a removable flow conditioner sized and arranged to fit
in the receptacle, fluid flowing from the inlet conduit into the
flow conditioner, through the elongate discharge nozzle to the
outlet; the flow conditioner having a plate with a plurality of
vanes defining a plurality of flow passageways so that an exit flow
path from all the passageways is oriented generally towards the
elongate discharge nozzle and outlet; and an adjustment assembly to
rotate and precisely align the flow conditioner, the vanes and the
flow passageways relative to the discharge passageway in the
elongate discharge nozzle and the outlet; a lock assembly to fix
the position of the flow conditioner after the flow conditioner,
the vanes and the flow passageways have been precisely aligned with
the elongate discharge nozzle and outlet; said adjustment assembly
having a slot formed in the removable flow diffuser; and, an
elongate adjustment stem having an eccentric cam on one end and an
adjustment knob on the other end, the eccentric cam engaging the
slot in the removable flow diffuser so rotation of the adjustment
knob causes rotation of the eccentric cam which imparts rotation to
the removable flow diffuser.
7. The apparatus of claim 6 wherein the lock assembly includes: an
elongate lock pin sized and arranged to fit in an elongate bore in
the cap; the lock pin threadibly engaging the bore so rotation of
the pin imparts axial movement to the lock pin causing it to move
away from or to engage with the flow conditioner to lock the flow
conditioner in position when the vanes and curvilinear passageways
are precisely aligned with the elongate discharge nozzle and the
outlet.
8. An adjustable diffuser connected to an inlet conduit and an
outlet conduit to reduce turbulence and/or pulsation as fluid flows
from the inlet conduit through the diffuser to the outlet conduit,
the adjustable diffuser comprising: a body defining an inlet, a
receptacle, an elongate discharge nozzle, and an outlet; a cap
removeably attached to the body, the cap allowing access to the
receptacle; a removable flow conditioner sized and arranged to fit
in the receptacle, fluid flowing from the inlet conduit into the
flow conditioner, through the elongate discharge nozzle to the
outlet conduit; the flow conditioner having a plate with a
plurality of vanes defining a plurality of flow passageways, some
of the flow passageways having a curvilinear orientation and some
having a generally radial orientation so that the fluid flowing
from all the passageways is directed generally towards the elongate
discharge nozzle and outlet; and an adjustment assembly to rotate
the flow conditioner to precisely align fluid flow from the flow
passageways to the discharge passageway in the elongate discharge
nozzle and the outlet.
9. The apparatus of claim 8 further including a lock assembly to
fix the position of the flow conditioner after fluid flow has been
precisely aligned with the elongate discharge nozzle and
outlet.
10. The apparatus of claim 9 wherein the adjustment assembly
includes: a plurality of gear teeth formed in the flow conditioner;
an elongate adjustment stem having a plurality of adjustment stem
gear teeth on one end and an adjustment knob on the other end so
rotation of the adjustment knob causes rotation of the adjustment
stem gear teeth; and the adjustment stem gear teeth engage the gear
teeth in the flow conditioner so rotation to the adjustment knob on
the adjustment stem causes rotation of the flow conditioner to
precisely align the fluid flow from the curvilinear passageways
with the elongate discharge nozzle and the outlet.
11. The apparatus of claim 9 wherein the lock assembly includes: an
elongate lock pin sized and arranged to fit in an elongate bore in
the cap; the lock pin threadibly engaging the bore so rotation of
the pin imparts axial movement to the lock pin causing it to move
away from or to engage with the flow conditioner to lock the flow
conditioner in position when fluid flow from the curvilinear flow
passageways is precisely aligned with the elongate discharge nozzle
and the outlet.
12. An adjustable diffuser connected to an inlet conduit and an
outlet conduit to reduce turbulence and/or pulsation as fluid flows
from the inlet conduit through the diffuser to the outlet conduit,
the adjustable diffuser comprising: a body defining an inlet, a
receptacle, an elongate discharge nozzle, and an outlet; a cap
removeably attached to the body, the cap allowing access to the
receptacle; a removable flow conditioner sized and arranged to fit
in the receptacle, fluid flowing from the inlet conduit into the
flow conditioner, through the elongate discharge nozzle to the
outlet conduit; the flow conditioner having a plate with a
plurality of vanes defining a plurality of flow passageways, some
of the flow passageways having a curvilinear orientation and some
having a generally radial orientation so that the fluid flowing
from all the passageways is directed generally towards the elongate
discharge nozzle and outlet; and an adjustment assembly to rotate
the flow conditioner to precisely align fluid flow from the flow
passageways to the discharge passageway in the elongate discharge
nozzle and the outlet; the apparatus of claim 8 further including a
lock assembly to fix the position of the flow conditioner after
fluid flow has been precisely aligned with the elongate discharge
nozzle and outlet; and the lock assembly includes: an elongate lock
pin sized and arranged to fit in an elongate bore in the cap; the
lock pin threadibly engaging the bore so rotation of the pin
imparts axial movement to the lock pin causing it to move away from
or to engage with the flow conditioner to lock the flow conditioner
in position when fluid from the curvilinear flow passageways is
precisely aligned with the elongate discharge nozzle and the
outlet.
13. An adjustable diffuser connected to an inlet conduit and an
outlet conduit to reduce turbulence and/or pulsation as fluid flows
from the inlet conduit through the diffuser to the outlet conduit,
the adjustable diffuser comprising: a body defining an inlet, a
receptacle, an elongate discharge nozzle, and an outlet; a cap
removeably attached to the body, the cap allowing access to the
receptacle; a removable flow conditioner sized and arranged to fit
in the receptacle, fluid flowing from the inlet conduit into the
flow conditioner, through the elongate discharge nozzle to the
outlet conduit; the flow conditioner having a plate with a
plurality of vanes defining a plurality of flow passageways, some
of the flow passageways having a curvilinear orientation and some
having a generally radial orientation so that the fluid flowing
from all the passageways is directed generally towards the elongate
discharge nozzle and outlet; and an adjustment assembly to rotate
the flow conditioner to precisely align fluid flow from the flow
passageways to the discharge passageway in the elongate discharge
nozzle and the outlet; a lock assembly to fix the position of the
flow conditioner after fluid flow has been precisely aligned with
the elongate discharge nozzle and outlet; and the adjustment
assembly having a slot formed in the removable flow diffuser; and,
an elongate adjustment stem having an eccentric cam on one end and
an adjustment knob on the other end, the eccentric cam engaging the
slot in the removable flow diffuser so rotation of the adjustment
knob causes rotation of the eccentric cam which imparts rotation to
the removable flow diffuser.
14. The apparatus of claim 13 wherein the lock assembly includes:
an elongate lock pin sized and arranged to fit in an elongate bore
in the cap; the lock pin threadibly engaging the bore so rotation
of the pin imparts axial movement to the lock pin causing it to
move away from or to engage with the flow conditioner to lock the
flow conditioner in position when the vanes and curvilinear
passageways are precisely aligned with the elongate discharge
nozzle and the outlet.
15. An adjustable diffuser connected to an inlet conduit and an
outlet conduit to reduce turbulence and/or pulsation as fluid flows
from the inlet conduit through the diffuser to the outlet conduit
comprising: a body defining an inlet, a receptacle, an elongate
discharge nozzle, and an outlet; a cap removeably attached to the
body, the cap allowing access to the receptacle; a removable flow
conditioner sized and arranged to fit in the receptacle, fluid
flowing from the inlet conduit into the flow conditioner, through
the elongate discharge nozzle to the outlet; the flow conditioner
having a plate with a plurality of vanes defining a plurality of
flow passageways so that an exit flow path from all the passageways
is oriented generally towards the elongate discharge nozzle and
outlet; and an adjustment assembly to rotate the flow conditioner
and precisely align the center vane with the discharge passageway
in the elongate discharge nozzle and the outlet.
16. The apparatus of claim 15 further including a lock assembly to
fix the position of the flow conditioner after the center vane in
the flow conditioner has been precisely aligned with the elongate
discharge nozzle and outlet.
17. The apparatus of claim 16 wherein the adjustment assembly
includes: a plurality of gear teeth formed in the flow conditioner;
an elongate adjustment stem having a plurality of adjustment stem
gear teeth on one end and an adjustment knob on the other end so
rotation of the adjustment knob causes rotation of the adjustment
stem gear teeth; and the adjustment stem gear teeth engage the gear
teeth in the flow conditioner so rotation to the adjustment knob on
the adjustment stem causes rotation of the flow conditioner to
precisely align the center vane with the elongate discharge nozzle
and the outlet.
18. The apparatus of claim 16 wherein the lock assembly includes:
an elongate lock pin sized and arranged to fit in an elongate bore
in the cap; the lock pin threadibly engaging the bore so rotation
of the pin imparts axial movement to the lock pin causing it to
move away from or to engage with the flow conditioner to lock the
flow conditioner in position when the center vane is precisely
aligned with the elongate discharge nozzle and the outlet.
19. An adjustable diffuser connected to an inlet conduit and an
outlet conduit to reduce turbulence and/or pulsation as fluid flows
from the inlet conduit through the diffuser to the outlet conduit,
the adjustable diffuser comprising: a body defining an inlet, a
receptacle, an elongate discharge nozzle, and an outlet; a cap
removeably attached to the body, the cap allowing access to the
receptacle; a removable flow conditioner sized and arranged to fit
in the receptacle, fluid flowing from the inlet conduit into the
flow conditioner, through the elongate discharge nozzle to the
outlet conduit; the flow conditioner having a plate with a
plurality of vanes defining a plurality of flow passageways, some
of the flow passageways having a curvilinear orientation and some
having a generally radial orientation so that the fluid flowing
from all the passageways is directed generally towards the elongate
discharge nozzle and outlet; and an adjustment assembly to rotate
the flow conditioner and precisely align the center vane with the
discharge passageway in the elongate discharge nozzle and the
outlet; said adjustment assembly having a pair of opposing axial
elongate set screws bearing against opposing sides of an adjustment
lug extending from the removable flow diffuser, the elongate set
screws threadibly engaging the body so rotation of one elongate set
screw and counter-rotation of the opposing set screw, causes
movement of the adjustment lug and the removable flow diffuser.
20. An adjustable diffuser connected to an inlet conduit and an
outlet conduit to reduce turbulence and/or pulsation as fluid flows
from the inlet conduit through the diffuser to the outlet conduit
comprising: a body defining an inlet, a receptacle, an elongate
discharge nozzle, and an outlet; a cap removeably attached to the
body, the cap allowing access to the receptacle; a removable flow
conditioner sized and arranged to fit in the receptacle, fluid
flowing from the inlet conduit into the flow conditioner, through
the elongate discharge nozzle to the outlet; the flow conditioner
having a plate with a plurality of vanes defining a plurality of
flow passageways to that an exit flow path from all the passageways
is oriented generally towards the elongate discharge nozzle and
outlet; and an adjustment assembly to rotate the flow conditioner
and precisely align the center vane with the discharge passageway
in the elongate discharge nozzle and the outlet; a lock assembly to
fix the position of the flow conditioner after the center vane in
the flow conditioner has been precisely aligned with the elongate
discharge nozzle and outlet; said adjustment assembly having a slot
formed in the removable flow diffuser; and an elongate adjustment
stem having an eccentric cam on one end and an adjustment knob on
the other end, the eccentric cam engaging the slot in the removable
flow diffuser so rotation of the adjustment knob causes rotation of
the eccentric cam which imparts rotation to the removable flow
diffuser.
21. The apparatus of 20 wherein the lock assembly includes: an
elongate lock pin sized and arranged to fit in an elongate bore in
the cap; and the lock pin threadibly engaging the bore so rotation
of the pin imparts axial movement to the lock pin causing it to
move away from or to engage with the flow conditioner to lock the
flow conditioner in position when the vanes and curvilinear
passageways are precisely aligned with the elongate discharge
nozzle and the outlet.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a flow diffuser with an elongate
discharge nozzle which can be used as a 90.degree. elbow in piping
systems. The flow diffuser can be located in or immediately
upstream of a measurement station or custody transfer station to
improve measurement accuracy. The flow diffuser promotes laminar
fluid flow and reduces pulsation in gas pipelines.
2. Description of the Prior Art
In piping systems, orderly or streamlined flow is desirable. When a
fluid passes through a conventional valve or a 90.degree. turn at a
conventional elbow, the fluid flow becomes disorderly or turbulent.
This turbulent fluid does not return to a streamlined or laminar
flow for at least 40-50 pipe diameters downstream of an elbow.
(Assuming that the downstream piping is axially aligned with the
outlet of the valve or elbow and has the same inside diameter.)
Turbulence can be caused by a number of factors including, but not
limited to, boundary layer separation, sometimes referred to as
flow separation, vortices, pressure waves and/or cavitation.
Turbulence in pipe systems often causes noise, vibration, erosion
and/or stress cracking. Reduction of turbulence is desirable in
valves, at elbows and in piping systems generally, both upstream of
gas or liquid measurement and downstream of compressor
stations.
Turbulence also causes a drop in fluid pressure. Each time a fluid
flows through a valve or elbow, there is an incremental drop in
fluid pressure between the inlet and the outlet. In transmission
pipelines, pressure drops are undesirable. If the fluid pressure
drops low enough, additional pumping stations may be required. In
any event, adding pressure to the fluid in the pipeline increases
transportation costs. Because the elbow of the present invention
reduces turbulence, it has less of a pressure drop when compared
with conventional 90.degree. elbows.
Elbow induced turbulence has been recognized and addressed by a
number of prior art designs including the vanes of U.S. Pat. No.
5,197,509 and No. 5,323,661 which are located upstream from an
elbow. These vanes impart rotation to the fluid as it passes
through the elbow to reduce downstream turbulence. Others have
considered the deleterious effects of elbow induced turbulence and
have included rotation vanes both upstream and downstream of an
elbow as described in U.S. Pat. No. 5,529,084. These inventions
seek to create non-turbulent or laminar flow after fluid passes
through a conventional elbow.
The use of curved vanes to influence fluid flow for various reasons
is not a new concept. In U.S. Pat. No. 1,570,907, a plurality of
vanes were used in a locomotive to separate water from steam.
Japanese Patent Application Serial Number Sho58 (1983)-13899 was
filed on Jan. 31, 1983 by Yamatake Honeywell Co. Ltd. for a Valve
Seat for Control Valve and Its Manufacturing Method. This prior art
valve discloses a comb-like cylinder equipped with multiple teeth
of rectangular cross-section formed as one piece with the
ring-shaped valve seat. These teeth may be formed at the lower end
of the valve seat on the outlet side or may be formed at both the
upper and the lower end of the valve seat. The manufacturing method
of the valve seat occurs sequentially. First, multiple slits are
formed in the radial direction on the cylindrical wall joined to
the ring-shaped valve seat as one piece. Then the rectangular teeth
forming these slits are twisted plastically (i.e., by exerting
torsional moments at the tip of the teeth large enough to cause
permanent deformation) so that each slit is oriented in the
direction of the fluid flow at its respective position. Because of
the rectangular shape of these teeth, they promote turbulence
instead of encouraging laminar flow.
In some piping systems, granular or particulate material will
quickly wear out a conventional elbow. One way to address this
problem is by increasing the radius of curvature of the elbow to
about 10 pipe diameters. However, this is not an entirely
acceptable solution, especially in areas where space is at a
premium. There have been many attempts to solve this erosion
problem, including the use of inserts in the elbow, the insert
being a disposable item intended to be replaced when it wears out.
Examples of this type of replaceable insert in an elbow can be
found in the following U.S. Pat. No. 1,357,259; No. 2,911,235; No.
3,942,684; and No. 5,590,916.
Other proposed solutions to this erosion problem include a circular
pocket off the elbow. This pocket accumulates a certain quantity of
the particulate material which serves as a pad to absorb the blow
of the subsequent material to reduce the erosive effects thereof as
shown in U.S. Pat. No. 4,387,914 and No. 5,060,984.
Conventional valves are also known to create turbulence and a
pressure drop between the inlet and the outlet. Robert H. Welker,
the inventor herein and the inventor of U.S. Pat. No. 5,730,416,
has developed various approaches to deal with valve induced
turbulence. In another patent, U.S. Pat. No. 5,769,388, Mr. Welker
has developed a plurality of vanes and passageways in the valve to
reduce turbulence. The apparatus shown in U.S. Pat. No. 5,769,388
has certain shortcomings because of the short discharge nozzle
which tapered at an included angle of approximately 12.degree..
There is still a need to reduce turbulence in elbows, in valves and
in piping systems in general.
In a gas pipeline, pulsation is normally caused by reciprocating
compressors and can be caused to a lesser degree by certain types
of check valves. Pulsation in a gas pipeline is typically the
result of the pistons in a reciprocating compressor pushing the gas
out in distinct pressure waves which may move five to ten miles
downstream of a pumping station. Pulsation is never desirable.
Liquid pipelines reduce pulsation by installing pulsation
dampeners, many of which commercially available. Pulsation in a
liquid pipeline can cause failure. The present invention should
reduce pulsation in a liquid pipeline.
The present invention should also reduce pulsation in gas
pipelines. Pulsation in gas pipelines can cause measurement error
at custody transfer stations and other measurement installations.
Pulsation pressure waves require sensitive instruments to be
detected.
The traditional solution to reduce pulsation in a gas pipeline is a
pulsation dampener, for example, those produced by Burgess Manning
Corp. of Cisco, Tex. 76437.
Prior art pulsation dampeners typically cause at least a 15 psi
permanent pressure drop in the pipeline. The present invention will
reduce pulsation in a gas pipeline with only a nominal pressure
drop, i.e., less than 5 psi.
BRIEF SUMMARY OF THE INVENTION
The present invention can be used as a 90.degree. elbow in piping
systems to reduce turbulence and pulsation. The elbow, sometimes
referred to as a flow diffuser, is connected to an inlet conduit
and an outlet conduit. The flow diffuser includes a convenient top
entry design allowing access to the removable flow conditioner.
Downstream of the flow conditioner is a transition zone, and an
elongate tapered discharge nozzle. Fluid flows from the inlet
conduit into the flow diffuser, through the flow conditioner, the
transition zone, and the elongate tapered discharge nozzle to the
outlet conduit.
The removable flow conditioner includes a plurality of vanes
defining a plurality of passageways to guide the fluid flow from
the inlet into the transition zone and elongate tapered discharge
nozzle. The purpose of the guide vanes is to reduce asymmetric
flow, swirling, jetting and other turbulence and to promote a
symmetric velocity profile and/or laminar flow as the fluid turns a
90.degree. corner. In gas pipelines, the vanes also reduce
pulsation. The flow conditioner can be fabricated as a replaceable
part to facilitate maintenance of the flow conditioner. One way to
develop a symmetric velocity profile is the design of the vanes and
passageways in the replaceable flow conditioner. The width of the
outlets from the passageways may be non-uniform in order to promote
streamlined flow.
After the flow diffuser has been fabricated, it is desirable to
test and align the flow conditioner for maximum effectiveness
before it is shipped to the field. This alignment process may only
require minor adjustments to properly orient the flow conditioner
relative to the discharge nozzle. After the adjustments have been
made the flow conditioner will need to be locked in place. In some
embodiments, the adjustment mechanism and the locking mechanism are
separate structures. In one alternative embodiment with opposing
set screws, the adjustment mechanism also locks the flow diffuser
in place. In some situations it may also be desirable to further
calibrate/adjust the flow diffuser in tandem with a meter after
both have been installed in the field.
The flow diffuser can be used in piping systems with liquids,
gases, and steam, as well as two-phase flow, three-phase flow, and
dry particulate and granules.
BRIEF DESCRIPTION OF THE DRAWINGS
So that the manner in which the above-identified features and
advantages of the present invention are attained and can be
understood in detail, a more particular description of the
invention, briefly summarized above, may be had by reference to the
embodiment thereof which is illustrated in the appended
drawings.
It is noted, however, that the appended drawings illustrate only a
typical embodiment of this invention and are therefore not to be
considered limiting of its scope, for the invention may admit to
other equally effective embodiments. Reference the appended
drawings, wherein:
FIG. 1 is a section view of the flow diffuser in exploded view.
FIG. 2 is a section view of the flow diffuser of FIG. 1 fully
assembled.
FIG. 3 is a section view of the flow diffuser along the line 3--3
of FIG. 2.
FIG. 4 is an enlarged partial section view of the adjustable flow
conditioner, vanes and passageways of FIG. 3.
FIG. 5 is an enlarged partial section view of the adjustment
assembly, the locking assembly, and the adjustable flow conditioner
of FIG. 2.
FIG. 6 is an enlarged perspective view of the removable flow
conditioner of FIG. 3.
FIG. 7 is a section view of the rectangular inlet of the discharge
passageway in the elongate discharge nozzle at the line 7--7 of
FIG. 1.
FIG. 8 is a section view of the polygonal interior surface of the
discharge passageway in the elongate discharge nozzle at the line
8--8 of FIG. 1
FIG. 9 is a section view of the polygonal interior surface of the
discharge passageway in the elongate discharge nozzle at the line
9--9 of FIG. 1.
FIG. 10 is a section view of the circular outlet of the discharge
passageway in the elongate discharge nozzle at the line 10--10 of
FIG. 1.
FIG. 11 is an enlarged perspective view of the bottom of the
removable flow conditioner of FIG. 3.
FIG. 12 is an enlarged partial section view of an alternative
embodiment of the adjust assembly using opposing set screws to
rotate the flow conditioner.
FIG. 13 is an enlarged perspective view of an alternative
embodiment of the adjustment mechanism using an eccentric cam.
FIG. 14 is a top view of the eccentric cam.
FIG. 15 is a schematic view of the test apparatus used during the
adjustment process for the flow diffuser.
DETAILED DESCRIPTION OF THE INVENTION
Referring now to FIG. 1, a flow diffuser is generally identified by
the numeral 10 and is shown in exploded view. The top of the flow
diffuser 10 is generally identified by the arrow 11 and the bottom
is generally identified by its numeral 13. The flow diffuser is
configured as a 90.degree. elbow 10 to be used in a piping system,
not shown. The flow diffuser 10 has a body 12 which defines an
inlet 14 and an outlet 16. An inlet conduit, not shown in the
drawing, has a flange that aligns and mechanically connects by a
bolt circle to the inlet flange 18 of the elbow 10. The inlet
flange 18 has a plurality of bolt holes, for example at 20 and 22
which receive the bolts for securing the inlet conduit flange to
the inlet flange 18 of the flow diffuser 10. An outlet conduit, not
shown in the drawing, has a flange which aligns and is connected to
the outlet flange 24 of the flow diffuser 10 by a bolt circle. The
outlet flange 24 of the flow diffuser 10 has a plurality of bolt
holes, for example at 26 and 28 which align with the bolt holes in
the outlet conduit flange. The alignment and connection of the
inlet conduit flange and the outlet conduit flange to the flanges
18 and 24 of the elbow 10 in a piping system is well known to those
skilled in the art.
To reduce turbulence and/or pulsation the inside diameter of the
inlet 14 should be about the same as the inside diameter of the
inlet conduit. To reduce turbulence and/or pulsation the inside
diameter of the outlet 16 should be about the same as the inside
diameter of the inlet conduit. To reduce turbulence and/or
pulsation, the inside diameter of the outlet conduit should also be
about the same as the inside diameter of the inlet conduit.
In FIG. 1 bolt holes 20, 22, 26 and 28 are shown at a 12 o'clock
and 6 o'clock position merely for illustrative purposes. One
skilled in the art will recognize that the actual locations of
these bolt holes are out of hand about 16" from the position shown
in these drawings for a 4-inch flange.
Fluid flows from the inlet conduit, not shown, into the inlet 14,
past the throat 29, through the flow conditioner 30, into the
transition zone 32, through the discharge passageway 33 of the
elongate tapered discharge nozzle 34, through the outlet 16, and
finally into the outlet conduit, not shown in the drawing. The
present invention can reduce turbulence and/or pulsation in gas
pipelines, such as those that transport natural gas and other
hydrocarbons, and it can reduce turbulence in liquid pipelines such
as those that transport water, gasoline, diesel and other
hydrocarbons. It can be used for two-phase flow, such as a cold
slurry or natural gas with entrained liquids. It can also be used
with three-phase flow, such as oil, water and gas. It can be used
with steam and it can be used with dry particulate or granules. For
purposes of this application, all of the foregoing will simply be
referred to as fluid.
The elbow 10 includes a removable cap 36. The cap 36 can be
threadably attached to the body 12, or attached by other means well
known in the art, such as a plurality of bolts 15 and 17. The elbow
includes several primary components, as follows: a removable and
adjustable flow conditioner 30, a transition zone 32, and a
discharge passageway 33 in the elongate tapered discharge nozzle
34. The flow conditioner 30 is manufactured as a separate part that
is inserted into receptacle 38 in the body 12 by removing the cap
36. Once the removable flow conditioner 30 is inserted into the
receptacle 38 of the body 12, the cap 36 is replaced and secured.
In some conditions, the flow conditioner may experience more wear
than other components in the elbow 10. To facilitate maintenance
and prolong the life of the flow diffuser 10, the flow conditioner
is replaceable.
When fluid passes through a conventional 90.degree. elbow in a
piping system, turbulence is generated because of the 90.degree.
turn. Conventional wisdom indicates that laminar flow does not
return to the fluid stream after it passes through a 90.degree.
elbow until as much as 40 to 50 pipe diameters past the elbow
(assuming an axially aligned straight discharge pipe having the
same inside diameters as the elbow). For example, with a
conventional 2 inch elbow and 2 inch piping system, laminar flow
may not return until as much as 80 inches to 100 inches downstream
of the elbow. It is desirable for many reasons to restore laminar
flow as quickly as possible after a fluid passes through a
90.degree. elbow. A length of 40 or 50 pipe diameters is simply
impractical in many real world applications.
The present invention restores substantially laminar flow to a
fluid stream after it passes through the 90.degree. turn within
about 4 pipe diameters after the transition zone 32. Reducing the
distance necessary to achieve substantially laminar flow from 40 or
50 pipe diameters to about 4 pipe diameters is an advantage in a
number of situations, especially in close quarters, such as
offshore drilling or production platforms. In addition, the flow
diffuser 10 is able to restore laminar flow after the fluid passes
through this 90.degree. turn with reduced noise and vibration when
compared with conventional elbow.
Reduction in noise and vibration is accomplished because of the
reduced turbulence in the elbow 10 when compared with prior art
elbows. Pulsation in gas pipelines is reduced because molecules
entering the elbow at the same time arrive at the outlet at
slightly different times due to some having to travel through a
longer passageway (flow path). Therefore, the voids between
pressure waves are filled in; thus, no pressure wave will exist at
the outlet 16.
To function properly, the flow conditioner 30 must be aligned
properly in the receptacle 38. An adjustment assembly generally
identified by the numeral 31 allows proper alignment of the flow
conditioner 30 with the discharge passageway 33 of the elongate
tapered discharge nozzle 34. The adjustment assembly 31 includes an
adjustment stem 35 with a pivot point 37 on one end and an
adjustment knob 39 on the other end. A plurality of gear teeth 41
are formed on the stem 35 proximate the pivot point 37. The gear
teeth 41 are sized and arranged to engage teeth 69 formed in the
flow conditioner 30. Rotation of the knob 39 imparts rotation to
the stem 35 and teeth 41 which engage the teeth 69 on flow
conditioner 30. Thus, rotation of knob 39 causes the flow
conditioner 30 to rotate in the receptacle 38. The stem 35 fits
through a bore 43 in the cap 36 and is sealed by a plurality of
chevron seals 45.
After proper adjustment of the flow conditioner 30, it is necessary
in this embodiment to use a locking assembly 47 to lock the flow
conditioner 30 in place. An elongate stem 49 has a point 51 on one
end and a knob 53 on the other end. The point 51 bears against the
flow conditioner 30 to lock it in the proper orientation. A lock
nut 55 locks the stem 49 against the cap 36. The stem 49 fits
through a bore 57 in the cap 36 and is sealed by an O-ring 59 which
is positioned in groove 61.
FIG. 2 is a section view of the flow diffuser 10 of FIG. 1, with
the cap 36 and flow conditioner 30 assembled for operation. The
flow conditioner 30 has a flat bottom plate 42. The guide vanes 50
A-P extend upward from the bottom 42 of flow conditioner 30. As a
matter of manufacturing choice, it would be equivalent to invert
the flow conditioner 30 so the vanes extended downward from a flat
top plate, not shown. If the flow conditioner was produced in this
equivalent fashion, minor changes would need to be made to the
receptacle and cap so the conditioner would align with the
transition zone 32 and the passageway 33 of elongate discharge
nozzle 34. Body 12 forms a side wall 44 surrounding the flow
conditioner 30. The side wall 44, the cap 36 and the bottom plate
42 contain the fluid flow in the flow conditioner 30. The flow
conditioner 30 includes an inlet port and an outlet port identified
generally by the dotted curved line 46 better seen in FIG. 3. The
outlet port 46 is defined by the side wall 44, the cap 36 and the
bottom surface 42 of the flow conditioner 30.
The inlet 14 feeds the fluid through an inlet port 79 into an inlet
zone 48 better seen in FIG. 3. A generally conical protrusion 54 is
attached to the cap 36 by bolt 62 which is sealed to cap 36 by seal
64. The conical protrusion 54 extends into the inlet zone 48 of
flow conditioner 30. The area of the inlet zone 48 is reduced by
the area of the generally conical protrusion 54; however, in the
preferred embodiment, the inlet zone 48 has an area at least twice
the cross-sectional area of the inlet 14. The conical protrusion 54
is replaceable, but as a matter of manufacturing choice, it would
be equivalent to form the conical protrusion as a part of the cap
36 or as a part of the flow conditioner 30.
FIG. 3 is a section view of the flow diffuser 10 along the line
3--3 of FIG. 1 except the conical protrusion 54 is not shown. In
other words, FIG. 3 is a section view of the flow diffuser 10
viewed from the top 11. The rear vane 50 A has a cutout area 56 and
a plurality of teeth 69 formed therein. The teeth 41 formed on the
stem 35 of the adjustment assembly 31 engage the teeth 69 on the
rear vane 50 A of flow conditioner 30. Rotation of knob 39 causes
stem 35 and teeth 41 to rotate. This imparts rotation to the flow
conditioner 30 in receptacle 38. The flow conditioner 30 is
adjusted after manufacture and before the flow diffuser 10 is
shipped to the field.
Vanes 50 A-P define a plurality of passageways 52 A-P. In the
preferred embodiment, 16 passageways are shown; however, a larger
number or a smaller number of passageways can be used depending on
the fluid matrix, pressure, pipe size and other operational
parameters. The side wall 44 of the body 12 together with the cap
36 and the bottom 42 direct fluid flow as it exits the passageways
52 A-P. The guide vanes have a generally heart-shaped outline. Each
passageway 52 has a beginning 58 and an ending 60. The beginning 58
in fluid communication with the inlet zone 48 and the ending 60 is
in fluid communication with the transition zone 32. In the
preferred embodiment, the area of each beginning 58 has a
cross-sectional area that is about twice as large as the
cross-sectional area of the end 60. The width of each passageway 52
at the beginning 58 is preferably equal to the circumference of the
inlet zone 48 divided by the number of passageways 52. The area of
the beginning 58 and the end 60 of each passageway 52 may be
modified during manufacture depending on the fluid matrix,
pressure, pipe size and other operational parameters. The ends 60
of each passageway 52 A-P may have different widths in order to
achieve the optimum velocity profile described in FIG. 15,
below.
The taper of the discharge nozzle 34 is important to reduce
turbulence of the fluid as it passes from the transition zone 32
towards the outlet conduit. Applicant prefers a taper with an
included angle of about 5.degree.-7.5.degree.. The included angle
of taper will determine the length of the discharge nozzle 34 as
shown in the table below.
Discharge Nozzle Lengths Diameter of Inlet Conduit 7.degree.
Included Angle 5.degree. Included Angle 1" App. 4.1" App. 6.53" 2"
App. 8.2" App. 13.05" 4" App. 16.4" App. 26.11" 6" App. 24.5" App.
39.16" 8" App. 32.7" App. 52.22" 12" App. 49.1" App. 78.33"
As indicated in this table, a discharge nozzle 34 tapered at a
7.degree. included angle will have a length approximately 4 times
the diameter of the inlet conduit. A discharge nozzle tapered at a
5.degree. angle will be longer and have a length approximately 61/2
times the diameter of the inlet conduit.
As shown in FIG. 3, the interior surface 66 of the discharge nozzle
34 has a taper of 3.5.degree. on all surfaces as measured from
lines extended parallel to the outlet conduit. The tapered
discharge nozzle 34 extends from the line 7--7 to the line 10--10.
The parallel lines in the drawing extend parallel to the walls of
the outlet 16. The outlet 16 has parallel sides aligned with the
outlet conduit to reduce turbulence.
In FIG. 4, an enlarged section view of the flow conditioner 30
similar to the view in FIG. 3 without the conical protrusion 54.
Fluid flows form the inlet 14 into the inlet zone 48 which has a
larger area than the cross-sectional area of the inlet 14. The
fluid encounters the conical protrusion 54, the guide vanes 50 A-P
and the beginning 58 of each curvilinear passageway 52 A-P as shown
by the flow arrows. The fluid then passes through the passageways
52 A-Q and moves into the transition zone generally identified by
the numeral 32. The transition zone 32 is defined by an upper
portion 70 and a lower portion 72 of the body 12 and a curved outer
wall 74, which is likewise a portion of the body 12. In the
preferred embodiment, the curved outer wall 74 has a radius about
21/2 times the diameter of the inlet 14. The transition zone 32 is
in fluid communication with the outlet opening 46 of the flow
conditioner 30, and the elongate tapered discharge nozzle 34. The
diameter of the flow conditioner from point R to point S in the
preferred embodiment is approximately 3 times the diameter of the
inlet 14.
Some of the passageways, i.e., 52 H and 52 I are aligned radially
relative to the inlet zone 48 and some are curvilinear, i.e., 52 A
and 52 P. This combination of radial and curvilinear passageways
reduces turbulence as fluid passes through the flow diffuser 10. In
addition, all of the vanes 50 A-50 P have a streamlined leading
edge 81 and a streamlined trailing edge 83 which also reduces
turbulence as fluid passes through the flow diffuser 10.
FIG. 5 is an enlarged section view of the adjustment assembly 31
and the locking assembly 47. The removable cap 36 is attached to
the body 12 by a plurality of bolts. Bolt 17 passes through bore 19
in cap 36 and threadibly engages bore 21 in body 12. In this view,
the point 51 of stem 49 is in engagement with the top surface of
the rear vane 50 A of the flow conditioner 30 to hold it in a fixed
position. Lock nut 55 is abutting cap 36, thus holding the stem 49
in a locked position. An O-ring groove 63 surrounds the cap 36.
O-ring 65 is positioned in the groove 63 to form a seal between the
body 12 and the removable cap 36. Chevron seals 45 form a seal
between the stem 35 and the bore 43 of the cap 36. O-ring 59 forms
a seal between the stem 49 and the bore 57 of the cap 36.
Adjustment of the flow conditioner 30 occurs after the diffuser 10
has been manufactured but before it has been shipped to the
field.
FIG. 6 is a perspective view of the top side of the removable flow
diffuser 30. Vanes 50 A-P extend upward from a flat bottom plate
42. Teeth 69 are formed in a cutout 56 in the rear vane 50 A. The
center vane 50 I is located opposite the rear vane 50 A.
FIG. 7 is a section view of the discharge nozzle 34 along the line
7--7 of FIG. 1. The interior surface 86 of the discharge nozzle 34
defines a discharge passageway 33 with a generally rectangular
shaped inlet 88. In the preferred embodiment, the height of the
rectangular shaped inlet 88 is about 1/2+L the diameter of the
inlet 14 and the width of the rectangular inlet 88 is about 1.5
times the diameter of the inlet 14. However, other dimensional
configurations for this rectangle fall within the scope of this
invention and may be adjusted, depending upon the fluid matrix,
pressure, pipe size, and other operational parameters.
FIG. 8 is a section view of the discharge nozzle 34 along the line
8--8 of FIG. 1. The interior surface 86 begins to change shape from
the generally rectangular inlet 88 to a polygon as shown in the
drawing. Other polygonal shapes fall within the scope of this
invention, provided that the interior surface 86 maintains a taper
with an included angle of about 5.degree.-7.5.degree..
FIG. 9 is a section view of the discharge nozzle 34 along the line
9--9 of FIG. 1. The interior surface 86 is polygonal. Other
polygonal shapes fall within the course of this invention, provided
that they are tapered as discussed above.
FIG. 10 is a section view along the line 10--10 of FIG. 1 showing
the discharge nozzle 34 as it converges to a circular outlet 90.
The diameter of the circular outlet 90 is approximately equal to
the diameter of the inlet 14. The inlet conduit and the outlet
conduit should be approximately equal in diameter and
cross-sectional area to reduce turbulence. The cross-sectional area
of the discharge passageway 33 as it extends from line 7--7 to line
10--10 for a 7.degree. included angle is about 4 times the diameter
of the inlet 14. The length of the discharge nozzle 34 from the
line 7--7 to the line 10--10 with a 5.degree. included angle is
about 61/2 times the diameter of the inlet 14. FIG. 10 the elbow 10
is viewed from the bottom 13.
FIG. 11 is a bottom perspective view of the removable flow
conditioner 30. The vanes 50 A-P extend upward from the flat bottom
plate 42. An inlet port 79 is formed in the bottom plate 42. In the
rear of the flow conditioner 30 is the rear vane 50 A. A cutout 56
is formed in the rear vane 50 A and the bottom plate 42. Teeth 69
are formed in the cutout 56 to permit adjustment of the flow
conditioner 30.
FIG. 12 is an alternative embodiment of the adjustment assembly. In
this alternative embodiment of the adjustment assembly, no separate
locking assembly is needed, because opposing set screws 132 and 134
are self locking.
In FIG. 12 a modified flow diffuser 130 has a lug 136 formed on the
rear vane 150 A. Set screw 132 engages one side 138 of the lug 136
and set screw 134 engages the other side 140 of the lug 136. The
set screw 132 threadibly engages bore 142 in the body 12 and set
screw 134 threadibly engages bore 144 in the body 12. When set
screw 132 is turned clockwise and set screw 134 is turned
counter-clockwise, the flow diffuser 130 rotates counter-clockwise,
and vice versa.
A seal 146 surrounds the head of screw 148 and creates a seal
between the body 12 and the screw 148. The screw 148 must be
removed from bore 142 in order to rotate the set screw 132. A seal
150 surrounds the head of screw 152 and creates a seal between the
body 12 and the screw 152. The screw 152 must be removed from bore
144 in order to rate the set screw 134.
FIG. 13 is a second alternative embodiment of the adjustment
assembly. In the second alternative embodiment of the adjustment
assembly 231, a separate locking mechanism must be used to fix the
position of the flow conditioner 230.
In FIG. 13, a modified flow conditioner 230 has a slot 232 formed
in the rear vane 250 A. The stem 35 has an eccentric cam 234 formed
on the end opposite the knob 39. A projection 236 extends from the
eccentric cam 234 and engages the slot 232 in the rear vane 250 A.
When the knob 39 is rotated clockwise, the projection 236 bears
against slot 232, causing the flow conditioner 230 to rotate
clockwise and vice versa.
FIG. 14 is a top view of the eccentric cam 234. The projection 236
is shown in phantom.
FIG. 15 is a schematic of the test apparatus used to adjust the
flow conditioner after manufacture, but before it is shipped to the
field. A newly manufactured flow diffuser 10 is placed
approximately six pipe diameters upstream of the manometer 300 and
is connected to a pressurized source of fluid, not shown. A shut
off valve, not shown, is placed between the source of pressurized
fluid and the flow diffuser 10. A valve, not shown, is opened and
pressurized fluid flows through the flow diffuser 10 past the
manometer 300. The flow conditioner 30 is rotated using the
adjustment mechanism 31 based on the readout from the manometer
300. After precise alignment is achieved, the locking assembly 47
is secured and the flow conditioner 30 is fixed in position. The
flow diffuser 10 is then ready to be shipped to the field for
installation.
This final adjustment process is necessary because there may be
slight manufacturing imperfections in the flow conditioner 30 which
might create a bias in the fluid flow exiting the flow conditioner
30. Another reason for this final adjustment process is because
precise prealignment of the flow conditioner 30 with the passageway
33 in the elongate discharge nozzle 34 during manufacture is
difficult because the flow conditioner 30 is removable. Prior art
prealignment pins simply do not always achieve the desired
precision due to manufacturing tolerances and assembly
requirements. Precise alignment can be achieved when fluid is
passing through the flow diffuser 10. Adjustments to the flow
conditioner 30 are typically very slight, and may only be 0.010
inch in one direction or the other.
The manometer 300 has a high pressure side 302 and a low pressure
side 304. In between is a U-shaped tube 306 typically filed with
water. The normal readout from a manometer is in inches of
water.
The high pressure side 302 is attached to an adjustable pitot probe
308 that can be moved up and down through the center of the
pipeline as shown in phantom. The low pressure side 304 is
connected to an inlet 310 that is fixed in position near the wall
of the pipeline.
The goal of the adjustment procedure is to achieve a symmetric
velocity profile in the flowing fluid downstream of the flow
diffuser 10. The shape of a symmetric velocity profile is sketched
in FIG. 15.
If the flow diffuser is inefficient or improperly adjusted,
asymmetric and/or turbulent fluid flow may result. Asymmetric and
turbulent flow are undesirable. If the adjustment procedure is not
precise, the velocity profile may be flattened or there may be
overrounding, both of which are undesirable. Overrounding results
in a conical velocity profile which is sometimes referred to as a
jet.
The American Gas Association (AGA) has various accuracy standards
for flow meters. Asymmetric flow, jetting, swirling and/or
pulsations may adversely affect accurate flow measurement.
According to AGA Transmission Measurement Committee Report No. 9 at
Section 7.2.2 "asymmetric velocity profiles may persist for 50 pipe
diameters downstream from the point of initiation. Swirling
velocity profiles may persist for 20 pipe diameters or more." The
present invention is designed to produce a symmetric velocity
profile without swirling or jetting. One way to enhance measurement
accuracy is to use a sufficient length of straight pipe (i.e.,
diameters) upstream of the meter so the fluid will develop a
symmetric velocity profile before it enters the meter. Another way
to enhance measurement accuracy is to place a well designed flow
diffuser upstream of the meter so the fluid will develop a
symmetric velocity profile before it enters the meter. Various flow
diffusers (also called flow conditioners) are available for this
purpose, such as the Vortab from Vortab Company of San Marcos,
Calif.; the CPA 50E plate from Canadian Pipeline Accessories
Company, Ltd. of Calgary, Alberta, Canada; or the GFC (Gallagher
Flow Conditioner) from Savant Measurement Corp. of Kingwood,
Tex.
The adjustment procedure for the present invention using the
apparatus in FIG. 15 is as follows. First, the pitot probe 308 is
placed in the center 312 of the pipe to measure the pressure of the
flowing fluid in the center of the pipe. Then the pitot probe 308
is placed near each pipe wall 314 and 316 to measure the pressure
of the flowing fluid near the walls. The highest pressure should be
in the center 312 of the pipeline and the lowest pressures should
be near the walls 314 and 316.
A symmetric velocity profile is desirable and has the same velocity
on either side of the center-line of the pipe. The optimum velocity
profile has a gentle curve or rounded nose as shown in FIG. 15. The
adjustable pitot probe 308 is moved back and forth across the
diameter of the pipeline from wall 314 to wall 316 to measure the
velocity of the flowing fluid. The flow conditioner 30 should be
adjusted so the velocity profile is as close as possible to the
optimum shape shown in FIG. 15. After adjustment, the flow
conditioner 30 should be locked in place with the locking mechanism
47. In some situations, it may also be desirable to further
calibrate/adjust the flow diffuser 10 in tandem with a meter after
both have been installed in the field.
Similar adjustments can be made to the flow conditioner 130 with
the first set screws 132 and 134 in the first alternative
embodiment of FIG. 12, except there is no separate locking
assembly. In other words, the opposing set screws 132 and 134 can
be tightened against the lug 136 to lock the flow conditioner 130
in place.
Similar adjustments can also be made to the flow conditioner 230
with eccentric cam 234 in the second alternative embodiment shown
in FIGS. 13 and 14. In the second alternative embodiment a separate
locking assembly 47 is required to fix the position of the flow
conditioner 230.
In some situations it may be difficult to obtain a pressurized
fluid source to adjust the flow conditioners 30, 130 or 230. In
these situations, the center vane 50 I may be optically aligned
with the center of the passageway 30 of the elongate discharge
nozzle 34.
* * * * *